How acceleration change if I use not forged wheels?
12-08-11, 01:19 AM
#20
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I know THAT THE LIGHTER IS BETTER. But i want to buy really nice wheels. Ideally if i will have enought money i will buy ADV 7.1 or HRE P40. But vossen weigt not much more than HRE P40. For example vossen weigth R20 x9=27 ibs, R20x10.5=28
HRE weight R20x9= 24.6 ibs and R20x10.5=26ibs
So the difference is 8.8 ibs
HRE weight R20x9= 24.6 ibs and R20x10.5=26ibs
So the difference is 8.8 ibs
Last edited by DIM; 12-08-11 at 01:25 AM.
12-08-11, 03:54 AM
#22
The wheels may be a few lbs more but the lower profile tires should be a few lbs less. It all balances out.
Let me add my .2 ct piece of information.
I refuse to believe a few more lbs is going to show on the clock of a track run. 20 lbs. yes but not 4-8 lbs. The taller wheels would be more of an issue. It takes longer to achieve top speed with bigger wheels because of circumsference. However, once top speed is achieves, It takes less energy to keep it there and more energy to stop it.
With a drag race, it balances out. On a track with turns there will be a disadvantage because it takes longer to achieve top speed and you'll have slow down often to handle turns.
I wouldn't abuse my pretty aftermarket wheels on a track anyway. Put the stockers on for the track.
Let me add my .2 ct piece of information.
I refuse to believe a few more lbs is going to show on the clock of a track run. 20 lbs. yes but not 4-8 lbs. The taller wheels would be more of an issue. It takes longer to achieve top speed with bigger wheels because of circumsference. However, once top speed is achieves, It takes less energy to keep it there and more energy to stop it.
With a drag race, it balances out. On a track with turns there will be a disadvantage because it takes longer to achieve top speed and you'll have slow down often to handle turns.
I wouldn't abuse my pretty aftermarket wheels on a track anyway. Put the stockers on for the track.
12-08-11, 11:27 AM
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when I wrote drag race I mean street racing on a city roads. And the most important thing is that i don't want to change figures on g-tech. With stock wheels I had 4.7 0-100 and over 4.48 0-60m/h
12-08-11, 05:08 PM
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Based on my not-so-accurate, not-scientific test, there is no difference in performance due to the wheels..
Last week, I had my winter tires installed (18*8 + 245/35 V18 Pirelli sottozeros. I don't know how heavy the wheels are, but the tire/wheel combo is definately lighter than the stock. I can feel the weight difference while lifting them)
After the change, my brother and I decided to find out what effect, if there is any, would result in with lighter wheels and tires. My brother has '11 IS-F (stock) and I have '09 (stock but 18 in. wheels/tires), so it was a nice set up.
We've picked a nice stretch at night and did some rolling drag runs from 20 mph in second gear to whatever mph to which the street condition allowed. We were consistantly able do to around 130-40 mph.
The result: Absolutely no difference in performance. Or, my car with lighter wheels/tires should have accelerated faster because I am heavier than my brother by 40 pounds?
Anyhow, lighter wheels (or anything) may be important at the track where 0.1 second counts, but I would say, based on my fun test, you can ignore the performance enhancement and go for a look you really want.
Last week, I had my winter tires installed (18*8 + 245/35 V18 Pirelli sottozeros. I don't know how heavy the wheels are, but the tire/wheel combo is definately lighter than the stock. I can feel the weight difference while lifting them)
After the change, my brother and I decided to find out what effect, if there is any, would result in with lighter wheels and tires. My brother has '11 IS-F (stock) and I have '09 (stock but 18 in. wheels/tires), so it was a nice set up.
We've picked a nice stretch at night and did some rolling drag runs from 20 mph in second gear to whatever mph to which the street condition allowed. We were consistantly able do to around 130-40 mph.
The result: Absolutely no difference in performance. Or, my car with lighter wheels/tires should have accelerated faster because I am heavier than my brother by 40 pounds?
Anyhow, lighter wheels (or anything) may be important at the track where 0.1 second counts, but I would say, based on my fun test, you can ignore the performance enhancement and go for a look you really want.
12-08-11, 07:14 PM
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Based on my not-so-accurate, not-scientific test, there is no difference in performance due to the wheels..
Last week, I had my winter tires installed (18*8 + 245/35 V18 Pirelli sottozeros. I don't know how heavy the wheels are, but the tire/wheel combo is definately lighter than the stock. I can feel the weight difference while lifting them)
After the change, my brother and I decided to find out what effect, if there is any, would result in with lighter wheels and tires. My brother has '11 IS-F (stock) and I have '09 (stock but 18 in. wheels/tires), so it was a nice set up.
We've picked a nice stretch at night and did some rolling drag runs from 20 mph in second gear to whatever mph to which the street condition allowed. We were consistantly able do to around 130-40 mph.
The result: Absolutely no difference in performance. Or, my car with lighter wheels/tires should have accelerated faster because I am heavier than my brother by 40 pounds?
Anyhow, lighter wheels (or anything) may be important at the track where 0.1 second counts, but I would say, based on my fun test, you can ignore the performance enhancement and go for a look you really want.
Last week, I had my winter tires installed (18*8 + 245/35 V18 Pirelli sottozeros. I don't know how heavy the wheels are, but the tire/wheel combo is definately lighter than the stock. I can feel the weight difference while lifting them)
After the change, my brother and I decided to find out what effect, if there is any, would result in with lighter wheels and tires. My brother has '11 IS-F (stock) and I have '09 (stock but 18 in. wheels/tires), so it was a nice set up.
We've picked a nice stretch at night and did some rolling drag runs from 20 mph in second gear to whatever mph to which the street condition allowed. We were consistantly able do to around 130-40 mph.
The result: Absolutely no difference in performance. Or, my car with lighter wheels/tires should have accelerated faster because I am heavier than my brother by 40 pounds?
Anyhow, lighter wheels (or anything) may be important at the track where 0.1 second counts, but I would say, based on my fun test, you can ignore the performance enhancement and go for a look you really want.
F-in genius
12-09-11, 02:04 PM
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12-09-11, 07:29 PM
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Below is what I posted to the same question on lexusfforum.com:
There are many different sites where you can find the math behind this, but from what I have read, every pound of unsprung weight makes a much greater difference on vehicle performance than the rest of the vehicle weight.
Going with heavier wheels isn't going to make a dramatic difference, but there will be a difference. Of course, everybody is interested in wheel weight, but usually nobody knows where that weight is concentrated. The more the weight is concentrated farther out from the center of the wheel, the more that weight will affect acceleration (i.e. light weight lug nuts won't make any difference at all because they are at the center of the rotating mass).
Also, along this same line of reasoning, the weight of the tire is more important that the weight of the wheel since the tire is located the farthest away from the center of the wheel and it's weight will affect the rotating mass the most.
Since you are looking at 20's, some of the wheel weight and all of the tire weight will be even farther away from the center of the wheel than with 19's, which will also further hinder acceleration...how much, I don't know. It will probably be very slight, but still noticeable.
There are many different sites where you can find the math behind this, but from what I have read, every pound of unsprung weight makes a much greater difference on vehicle performance than the rest of the vehicle weight.
Going with heavier wheels isn't going to make a dramatic difference, but there will be a difference. Of course, everybody is interested in wheel weight, but usually nobody knows where that weight is concentrated. The more the weight is concentrated farther out from the center of the wheel, the more that weight will affect acceleration (i.e. light weight lug nuts won't make any difference at all because they are at the center of the rotating mass).
Also, along this same line of reasoning, the weight of the tire is more important that the weight of the wheel since the tire is located the farthest away from the center of the wheel and it's weight will affect the rotating mass the most.
Since you are looking at 20's, some of the wheel weight and all of the tire weight will be even farther away from the center of the wheel than with 19's, which will also further hinder acceleration...how much, I don't know. It will probably be very slight, but still noticeable.